Why Tim Ferriss says hearing the word 'no' sets you up for success

As an early-stage investor and adviser to companies like Facebook, Alibaba and Uber, entrepreneur and bestselling author Tim Ferriss has spoken with hundreds of icons, CEOs and captains of industry.

But when Ferriss sought out leaders to share their advice for his new book "Tribe of Mentors," he still faced a surprising amount of rejection.

"I reached out to a lot of different people and there were a lot of non-responses, and then there were a fair number of polite declines," Ferriss tells CNBC's "Squawk Box."

Only after "thousands of back-and-forth emails and Twitter direct messages, hundreds of phone calls, many marathons at a treadmill desk, and more than a few late-night bottles of wine" did Ferriss gather the respondents that would make it into his new book.

And the author decided that the "no's" he had received in the process of putting his book together could serve a valuable lesson not just to himself but to others as well.

"Some of the emails were so incredibly well-crafted and so smart in the wordsmithing that they used," Ferriss says, that he asked if he could publish them as examples. He argued this would empower his readers to "copy and paste" that language to "make it easier to say no" to opportunities they needed to turn down.

"For instance, I was once refused for a lunch date with a very famous tech investor and he said, 'Sorry, I'm on a no-meeting diet for the next month and I have a policy of saying no to all meetings'," Ferriss recalls. "So I started using a 'no conference call diet' and people just rolled with it. It was incredible. There was no feedback, no push-back."

Ferriss says he hopes that readers will gain confidence and learn that "most losses or mistakes are really survivable." Realizing that can help you become more resilient and more likely to persevere.

In "Tribe of Mentors," Ferriss offers a collection of over 100 interviews with titans such as Maria Sharapova, Ray Dalio, Gretchen Rubin, Jimmy Fallon and Arianna Huffington for their advice on mentoring, leadership and life.

Ferriss asks everyone the same set of questions, a "fine-tuned" version of those which he has asked his past 300 guests on his business podcast "The Tim Ferriss Show."

Two he highlights from the book include, "What failure has set you up for later success, whether you knew it at the time or not?" and "What techniques or strategies do you have for saying no?"

Ferriss is known for tackling his own fear of failure head-on, as he detailed in a TED Talk earlier this year, but he says there is much to learn from hearing how others give and receive rejection.

He notes in the introduction to his book that "success can usually be measured by the number of uncomfortable conversations we are willing to have and by the number of uncomfortable actions we are willing to take."

To Ferriss, learning to say or hear "no" is a crucial part of getting ahead.